1. Introduction to Ecology
Biology 1
Introduction to Ecology

2. Ecology: the study of the relationships living things have with each other and their non-living environment.

3. Biotic Factors: all the living things in an environment
What biotic factors can you identify?

4. All the non-living factors in an environment.
Abiotic Factors:
All the non-living factors in an environment.
The soil (dirt) in an environment cannot be called simply abiotic or biotic. Discuss.
Note that dead things that were living are generally classified (there is some professional inconsistency) as abiotic but organic.

5. What does it mean that these sharks are different species?
Species: a group of organisms that can interbreed and produce fertile offspring in nature.
Note that there are many issues with the standard definition above. Part of that is due to simplification – the “gene pool” idea is too much for this course but is more relevant to actual ecology. However there are serious issues with the species definition at all – asexual species especially prokaryotes cannot be managed under this system (in fact the study and classification of bacteria is a young and active field with plenty of debate among professionals). It also does not work well when looking at evolutionary time; in almost all cases it would be clear that an organism is the same species as it children and its parents, but following the unbroken chain of ancestry clearly leads to other species over time.
A few shark species
What does it mean that these sharks are different species?

6. Vocabulary The place an organism lives. Habitat (address)
Think of a zoo. There is usually an attempt to mimic the organism’s “habitat.”
Niche (occupation)
The role that an organism plays in its environment.
How does the organism obtain food? What are some of its relationships with other organisms?
Can you describe the habitat and niche of some organisms?

7. Vocabulary: Levels of Ecology
Organism (any single living thing)
Population (members of same species living in one place)
Community (different populations interacting in an area)
Ecosystem (a complete community + its abiotic environment)
 Biosphere (all parts of Earth where life exists, both biotic and abiotic)

8. Population: a group of the same species living in the same area at the same time.

9. Community: interacting groups of populations

10. Ecosystem: a community and its abiotic environment.
light
A Freshwater Pond
humidity
Water temperature
Mineral
content

11. Biomes (not required): Large, ecologically similar areas.
There are other levels that we will not cover, as biomes above, ecozones, etc.

12. Biosphere: all the interdependent and interrelated ecosystems of the earth

13. Population Ecology: the interactions of one population, especially relating to population size
What increases population size?
Natality (births)
Immigration (moving into a population)
What decreases population size?
Mortality (deaths)
Emigration (moving out of a population)
What are some factors that would influence natality and mortality rates? Immigration and emigration?

14. Natural Resources:
Things organisms need to survive
Limiting Factors (environmental resistance):
When resources are in short supply (or too abundant) and impact population growth.

15. Compare and contrast these graphs.
Carrying capacity: the maximum population than an environment can sustainably support
Compare and contrast these graphs.
A population may plateau OR temporarily overshoot the carrying capacity. If overshot, survival depends of severity of overshoot and speed of environmental recovery.

16. Apply population ecology ideas to the global human population.
Human population hit 1 billion around 1800, 3 billion in 1960, and 7 billion in 2011.

17. COMMUNITY INTERACTIONS: Relationships between species
Effect
3 types of Symbiosis:
A continuing and close relationship between species
Mutualism
+ / +
Commensalism
+ / 0
Parasitism
+ / -
Pathogen / Host
Not considered symbiosis
Predator / Prey
Herbivore / Plant
Competition
- / -
Student should know the five relationships in yellow. Those in white are variations on the above relationships but students should not be tested on that vocab.

18. MUTUALISM: a + / + interaction Lichens: an alga and a fungus!
What benefit does each species receive?

19. MUTUALISM: a + / + interaction Cleaner Wrasse and Parrot Fish
Ants and Acacia Trees
What benefit does each species receive?

20. MUTUALISM: a + / + interaction
Aphids are grazed in herds by ants, who drink the sweet “honeydew” excreted by the aphids. The aphids feed on the plant phloem and the ants will tend, groom and even move the aphid herd as needed. Ants will also defend the aphids against predators like ladybugs. Clip 1: Start at time 0:30 – ants drinking honeydew less than a minute will be plenty. Clip 2: Ants attacking ladybug eating aphids, don’t need to watch the whole thing to get the idea.
Ants and Aphids

21. PARASITISM: a + / - interaction
Like predation, but the parasite feeds over an extended period of time, and only sometimes leads to the death of the prey organism.

22. PARASITISM: The Cuckoo
Cuckoo birds are social parasites – they don’t feed directly from the bodies of others but rather hijack the social relationship of parent and child. The female cuckoo rapidly lays her egg in the host bird’s nest. The cuckoo egg hatches faster and if able, will roll the other eggs out of the nest. The gaping red beak of the baby cuckoo exploits the host’s genetically programmed behavior evolved to ensure feeding to the young. Video: best times about 1:00 – 2:30. (Attenborough)

23. PATHOGEN / HOST: a + / - interaction

24. COMMENSALISM: a + / 0 interaction
Scavengers benefit from dead organisms that are not affected.
Cattle Egrets eat the insects that these cattle scare up.

25. COMMENSALISM: a + / 0 interaction Shark and Remora
The remora swim along under the shark and eat little bits of food that float past the shark when the shark feeds.

26. PREDATION: a + / - interaction

27. HERBIVORY: a + / - interaction
Not required vocab, but it we don’t really call grass the “prey” or sheep “predators”; those terms are reserved for when the consumed species is motile.

28. COMPETITION: a - / - interaction
Students should know that competition occurs within and between species but the vocab interspecific and intraspecific will not be tested. (Note also that intraspecific is population ecology while interspecific is community ecology).
Male weaver birds: compete to attract a mate. This is INTRASPECIFIC competition: competition within the same species

29. COMPETITION: a - / - interaction
Invasive starlings will out-compete native bluebirds for nesting holes. This is INTERSPECIFIC competition: competition between different species

30. Energy and Ecology:
ALL living things need both matter and energy.
Matter and energy are transferred:
between organisms
between organisms and the abiotic environment
What is different between the transfer of ENERGY and the transfer of MATTER?
ENERGY: flows one-way through the biosphere and leaves the Earth. A new input of energy is continually needed.
MATTER: the same atoms are use over and over again. Matter is recycled, not “lost”.

31. All organisms need energy to live.
Energy and Ecology
All organisms need energy to live.
Where do you get your energy?
How did the things you eat get their energy?
Trace the energy back to its source. What is the source of energy for (almost) all living things?

32. Ecology Vocabulary
Tip: Learn word parts to help you understand new terms:
Prefixes:
“Auto” = by itself
“Hetero” = from others
Base-word:
“Troph” = energy (obtaining food)
Sometimes you see the suffix:
“ic” = pertaining to
Can you think of examples of words that have these parts?

33. Trophic Levels: how organims obtain energy (their food)

34. All organisms need energy to live.
AUTOTROPHS (producers): Most use energy directly from the sun
produce their own food by photosynthesis in chloroplasts
often plants (also some bacteria, lichens, etc)
Also break down food when and where needed to release energy (respiration)
Important to emphasize that plants use oxygen (in respiration) as well as release it in photosynthesis. There would be little point for plants to store energy if they then never used it. Roots (underground, no light) have a metabolism (need energy). That is one of the reasons that plants have “sap” (phloem) that can transport sugars from where they are produced (during photosynthesis) to where they need to be used or stored (fruits, buds, roots, etc.)

35. All organisms need energy to live.
HETEROTROPHS get energy from consuming other organisms
often animals that release energy by respiration in their mitochondria

36. Two major types of Heterotrophs:
Consumer - a living thing that eats other living things to survive. It cannot make its own food.
Examples…humans, fish, spiders
We will skip detritivores, although the distinction can be seen in the earlier summary slide.
Decomposer - an organism that breaks down and digest the remains of organisms.
Examples…. fungi and some bacteria

37. Decomposers are essential because they are the nutrient recyclers!
Kinds of Decomposers: 1.) detritovore: (have a mouth) feed on dead organisms or their wastes eg. worms, millipedes, dung beetles 2.) Saprotroph: (without a mouth) secrete digestive enzymes into their environment and absorb the nutrients. eg. Bacteria, fungi

38. between Detritivores and Saprotrophs?
What is the difference
between Detritivores and Saprotrophs?
• Detritivores usually have mouths, Saprotrophs do not.
• Detritivores are mostly animals while saprotrophs are mostly bacteria and fungi.
• Detritivores consume lumps of dead organic matter separately, while saprotrophs absorb chemically digested food.
• Saprotrophs digest their food externally, whereas detritivores do it internally in their digestive system.

40. Remember to follow the energy!
Find several major errors / omissions in this diagram
(from a respected publisher!)

41. Food chain: One possible energy pathway through an ecosystem.
Shows who eats whom.
Let’s play “follow the energy!”
The arrows show you where it goes!

42. Food web: All possible energy pathways through an ecosystem.
Shows alternative food choices.
Although decomposers are crucial they are rarely shown just for visual reasons – they would need to connect to everything.

44. Trophic Levels and Levels of Consumers
Fourth Trophic Level
Third Trophic Level
Second Trophic Level
First Trophic
Level
Note that the trophic level is always one more than the consumer level. Why?

45. Food Web: Problems with Trophic Levels
What is the trophic level of the fox? 3 4 5 4 3 3 2 2 2 1 1 1

46. We know that energy is transferred. How much?
About 10% between trophic levels.
Trophic Level: Position in a food chain

47. Energy Efficiency in Food Consumption
Why is it said that eating vegetarian food can reduce food shortages and starvation?

48. Energy is not created or destroyed
Energy is not created or destroyed. If only 10% of energy is transferred to the next trophic level, where is the rest?
Why can only 10% of energy be transferred to the next trophic level?
Not all organisms are eaten
Not all parts of organisms can be digested
Converting energy for the functions of life is not 100% efficient (some is always) lost as heat

49. Cycles in Nature:
ALL living things need both matter and energy.
Matter and energy are transferred:
between organisms
between organisms and the abiotic environment
What is different between the transfer of ENERGY and the transfer of MATTER?
ENERGY: flows one-way through the biosphere and leaves the Earth. A new input of energy is continually needed.
MATTER: the same atoms are use over and over again. Matter is recycled, not “lost”.

50. Water, Carbon, Nitrogen, etc.
Cycles of Matter:
Water, Carbon, Nitrogen, etc.
CARBON CYCLE
Follow the carbon atoms.
Where do they go?
combustion
This is a good place to connect to our unit on combustion. Also, compare and contrast the movement of energy and atoms here.

51. Biodiversity
What does “Bio” mean?
Life
Bio =

52. Biodiversity
What does “Diversity” mean?
Diversity = Variety

53. There are 3 components of biodiversity
Diversity within genes Chihuahuas, beagles, and Rottweilers are all dogs—but they're not the same because their alleles are different.
Beagle
Chihuahua
Rottweilers

54. 3 components of biodiversity
2. Diversity of species For example, there about 260 species of monkeys, 5,000 species of dragonflies, and 350,000 species of flowering plants.
Golden Skimmer
Meadow Beauty
Saki Monkey

55. 3 components of biodiversity
3. Variety of ecosystems Prairies, Ponds, and tropical rain forests are all ecosystems. Each one is different and supports a unique set of species.
Paines Prairie
Florida Sand hill Pond
Hoh Rain Forest

56. Which has more biodiversity?

57. Threats to biodiversity
Habitat destruction or loss including
Land cleared for agriculture, construction, resource extraction, etc.
Climate change impacts
Pollution
2. Invasive Species
3. Direct hunting or exploitation
For a video about biodiversity watch “Extinction!” video from the evolution unit.

58. Why do we want biodiversity?
1. Intrinsic Value = Something that has value
in and of itself. Do we value all life?
2. Utilitarian Value = Something that has value as a means to an end. What do we get from biodiviersity?
Food, shelter, medicine, and other products
Stable ecosystems and epidemic-resistant species
Ideas for research and sources of new information

59. The Earth is losing species at an alarming rate
Some scientists estimate that dozens of species are going extinct each day, many of which humans never studied
This periwinkle was used in traditional medicine and became endangered due to habitat destruction. Scientists found that it has anti-cancer properties. It now gives us cisplatin, one of our best treatments for leukemia.
We came close to losing this species. What else might we be losing every day without knowing it?
Madagascan Rosy
Periwinkle

60. Solutions, not just problems
Eco-Tipping Points
Small actions that lead to large positive changes
For more information
A Thailand case study
Reversing Tropical Deforestation
Video presentation